<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="../../jquery.min.js"></script>
</head>
<body>
<select name="test" id="">
    <option value="1">测试一下</option>
    <option value="2" selected>我是2</option>
</select>

<script>
    $('select').on('change', function() {
        console.log($(this).children('option:selected').text());
        console.log($(this).children('option:selected').val());
    });
</script>
</body>
</html>